MXPA01001117A - Articles that include a polymer foam and method for preparing same - Google Patents

Abstract

Polymer foam articles having a substantially smooth surface prepared by melt-mixing a polymer composition and a plurality of microspheres, at least one of which is an expandable polymeric microsphere, under process conditions, including temperature and shear rate, selected to form an expandable extrudable composition;and extruding the composition through a die.

Description

ART CULTS THAT INCLUDE A POLYMER FOAM AND METHOD TO PREPARE THEM Field of the Invention This invention relates to the preparation of articles that include a polymer foam.

BACKGROUND OF THE INVENTION Articles incorporating a polymer are known. The foam includes a polymer matrix and is characterized by a density that is less than the density of the polymer matrix itself. The reduction in density is achieved in a number of ways, including through the creation of gaps filled with gas in the matrix (eg by means of a gas production agent) or the inclusion of polymeric microspheres (eg, expandable microspheres). ) or non-polymeric microspheres (eg, glass microspheres).

Brief Description of the Invention In a first aspect, the invention features an article that includes a polymer foam having a substantially smooth surface. The foam could be provided in a variety of forms, including a bar, a cylinder, a sheet, etc. In some Ref: 127003 embodiments, e.g., when the foam is provided in the form of a sheet, the foam has a pair of major surfaces, one or both are substantially smooth. The foam includes a plurality of microspheres, at least one of which is an expandable polymer microsphere. As used herein, a "polymer foam" refers to an article that includes a polymer matrix, wherein the density of the article is less than the density of the matrix alone. A "substantially smooth" surface refers to a surface having a Ra value less than about 75 micrometers, which is measured by means of laser triangulation profiling according to the procedure described in the examples, infra. Preferably, the surface has a Ra value of less than about 50 micrometers, more preferably less than about 25 micrometers. The surface is also characterized by the substantial absence of visually observable macroscopic defects such as wrinkles, corrugation and grooves. Furthermore, in the case of an adhesive surface, the surface is sufficiently smooth, such that it has inadequate contact and, therefore, adhesion to a substrate of interest. The level of adhesion The desired threshold will depend on the particular application for which the article is used. An "expandable polymeric microsphere" is a microsphere that includes a polymer coating and a core material in the form of a gas, liquid, or combination thereof, which expands upon heating. The expansion of the core material, in turn, causes the coating to expand, at least at the heating temperature. An expandable microsphere is one where the coating can initially expand or expand more without breaking. Some microspheres could have polymer coatings that only allow the core material to expand at or near the heating temperature. The article could be an adhesive or non-adhesive article. An "adhesive article" is an article that has an area available for bonding to that which is sticky at room temperature (ie, pressure sensitive adhesive articles) or which becomes sticky when heated (ie, adhesive articles activated by heating). . An example of an adhesive article is a foam that by itself is an adhesive, or an article that includes one or more separate adhesive compositions bonded to the foam, e.g., in the form of a continuous layer or discrete structures (e.g., strips, bars, filaments, etc.), in this case the foam alone does not need to be an adhesive. Examples of non-adhesive articles include non-adhesive foams and adhesive foams provided with a non-adhesive composition, e.g., in the form of a layer, substrate, etc., on all surfaces available for bonding.

Preferably the foam is substantially free of cross-linked urethane and cross-linked urea, thus eliminating the need for isocyanates in the composition. An example of a preferred material for the polymer foam is an acrylic polymer or copolymer. In some cases, e.g., when high cohesive force and / or high modulus is needed, the foam could be cross-linked. The polymer foam preferably includes a plurality of expandable polymeric microspheres. The foam could also include one or more non-expandable microspheres, which could be polymeric or non-polymeric microspheres (e.g., glass microspheres). Examples of preferred expandable polymeric microspheres include those in which the coating is essentially free of vinylidene chloride units. The preferred core materials are different air materials that are expands when heating The foam could contain agents in addition to the microspheres, the selection of these is dictated by the properties necessary for the projected application of the article. Examples of suitable agents include those selected from the group consisting of tackifiers, plasticizers, pigments, dyes, solid fillers, and combinations thereof. The foam could also include gaps filled with gas in the polymer matrix. Such gaps are typically formed by including a gas producing agent in the polymer matrix and then activating the gas producing agent, e.g., by exposing the polymer matrix to heating or radiation. The properties of the article could be adjusted by joining and / or coextruding one or more polymer compositions (e.g., in the form of continuous layers or discrete structures such as strips, bars, filaments, etc.) to or in the foam. Both foamed and non-foamed compositions could be used. A composition could be attached directly to the foam or indirectly, e.g., through a separate adhesive.

The article could be used as an "on-site foam" article. The term foaming on the site refers to the capacity of the Article to expand or expand further after the article has been placed in a desired location. Such articles are sized and placed in a recessed area or on an open surface, and then exposed to heating energy (eg, infrared, ultrasound, microwave, resistance, induction, convection, etc.) to activate, or activate more, the expandable microspheres or gas production agents. Such hollow areas may include a space between two or more surfaces (e.g., parallel or non-parallel surfaces) such as is found, for example, between two or more opposed and separated substrates, a through hole or a cavity. Such open surfaces may include a flat or irregular surface where it is desirable for the article to expand after it is applied to the surface. Upon activation, the foam expands due to the expansion of the microspheres and / or gas production agent, thereby partially or completely filling the gap or space, or thereby increasing the volume (e.g., height) of the article on the open surface. It may be desirable for the foam to contain a substantially uncrossed or thermoplastic polymer matrix material. It may also be desirable for the polymer matrix foam to present some degree of entanglement. Any entanglement should not inhibit or significantly prevent the foam from expanding to the desired degree. A potential advantage of such entanglement is that the foam will probably exhibit improved mechanical properties (e.g., increased cohesive strength) compared to the same foam with less or no interlacing. In the case that the foam has a curable polymer matrix, exposure to heat can also initiate the curing of the matrix. It may further be desirable that the foaming article on the site contain multiple layers, discrete structures or a combination thereof (see, for example, Figs 4-6 and the following discussion thereof), with each layer and structure discrete that have a difference in the way the foam forms on the site (eg, using expandable microspheres, gas production agents or a combination thereof), a difference in the degree to which it can be expanded on the site, or a combination of them. For example, the concentration of expandable microspheres and / or gas producing agents may be different, the type of expandable microspheres and / or gas producing agents may be different, or a combination thereof may be used. Also, for example, one or more of the discrete layers and structures may be expandable at the site, while one or more discrete layers and structures may be non-expandable at the site. In a second aspect, the invention highlights an article (eg, an adhesive article, as defined above) comprising a polymer foam (as defined above) that includes: (a) a plurality of microspheres, at least one of which is a microsphere expandable polymer (as defined above), and (b) a polymer matrix that is substantially free of urethane crosslinks and urea crosslinks. The matrix includes a mixture of two or more polymers in which at least one of the polymers in the mixture is a polymer of pressure sensitive adhesive (ie polymer that is inherently pressure sensitive, which precludes a polymer from combined with an adherent to form a pressure sensitive composition) and at least one of the polymers is selected from the group consisting of unsaturated thermoplastic elastomers, insoluble saturated acrylate thermoplastic elastomers, and non-pressure sensitive thermoplastic adhesive polymers. The foam preferably has a surface substantially smooth (as defined above). In some embodiments, the foam has a pair of major surfaces, one or both could be substantially smooth. The same foam could be an adhesive. The article could also include one or more separate adhesive compositions attached to the foam, e.g., in the form of a layer. If desired, the foam could be interlaced. The polymer foam preferably includes a plurality of expandable polymeric microspheres. It could also include non-expandable microspheres, which could be polymeric or non-polymeric microspheres (e.g., glass microspheres). The properties could be adjusted directly or indirectly by joining one or more foamed or unfoamed polymer compositions to the foam. The invention also highlights multi-layer articles including the foam articles described above provided with a larger surface area of a first substrate, or layered between a pair of substrates. Examples of suitable substrates include wood substrates, synthetic polymer substrates, and metal substrates (e.g., metal foils). In a third aspect, the invention highlights a method for preparing an article that includes: (a) mixing the melt of a polymer composition and a plurality of microspheres, one or more of which is an expandable polymeric microsphere (as defined above), under the conditions of the process, including temperature, pressure and shear rate, selected for forming a composition capable of extruding expandable; (b) extruding the composition through a nozzle to form a polymer foam (as defined above); and (c) at least partially expanding one or more expandable polymeric microspheres before the polymer composition leaves the nozzle. It may be preferable for most, if not all, expandable microspheres that expand at least partially before the polymer composition leaves the nozzle. By causing expansion of the expandable polymeric microspheres before the composition leaves the nozzle, the resulting extruded foam can be produced within narrower tolerances, as described later in the Detailed Description. It is desirable that the polymer composition be substantially free of solvent. That is, it is preferred that the polymer composition contains less than 20% p. of solvent, more preferably, contains substantially no more than about 10% p. of solvent and, even more preferably, contains no more than about 5% p. of solvent. In a fourth aspect, the invention features another method for preparing an article that includes: (a) mixing the melt of a polymer composition and a plurality of microspheres, one or more of which is an expandable polymeric microsphere (as defined) before), according to the process conditions, including temperature, pressure and shear rate, selected to form a composition capable of extruding expandable; and (b) extruding the composition through a nozzle to form a polymer foam (as defined above). After the polymer foam exits the nozzle, enough of the expandable polymer microspheres remain in the foam without expanding or, at most, partially expanded to allow the polymer foam to be used in a foaming application in the foam. site. That is, the extruded foam can be further expanded to a substantial degree at some time after application. Preferably, the expandable microspheres in the extruded foam retain most, if not all, of their expandability.

In a fifth aspect, the invention features another method for preparing an article that includes: (a) mixing the melt of a polymer composition and a plurality of microspheres, one or more of which is an expandable polymeric microsphere (as defined) before), according to the process conditions, including temperature, pressure and shear rate, selected to form a composition capable of extruding expandable; and (b) extruding the composition through a nozzle to form a polymer foam (as defined above) having substantially a smooth surface (as defined above). Whether it is possible to prepare foams having a pair of major surfaces in which one or both of the main surfaces are substantially smooth. The polymers used according to the present invention may preferably possess an average molecular weight of at least about 10,000 g / mol, and more preferably at least about 50,000 g / mol. It may also be preferable that the polymers used according to the present invention exhibit cut-off viscosities measured at a temperature of 175 ° C and a shear rate of 100 sec-1, of at least about 30 Pascal-seconds (Pa-s) , more preferably at least about 100 Pa-s and even more preferably at least about 200 Pa-s. The article could be an adhesive article (as defined above), e.g., a pressure sensitive adhesive article or a heat activated adhesive article. In some embodiments, the same foam is an adhesive.

Both the expandable extrudable composition and the extruded foam preferably include a plurality of expandable polymeric microspheres (as defined above). The extruded foam and the expandable extrudable composition could also include one or more non-expandable microspheres, which could be polymeric or non-polymeric microspheres (e.g., glass microspheres). Extendable extrudable compositions could be co-extruded with one or more additional extrudable polymer compositions, e.g., to form a polymer layer on a surface of the resulting foam. For example, the composition capable of extruding additional expandable could be an adhesive composition. Other additional extrudable polymer compositions include additional compositions that They contain microspheres. The method could also include the entanglement of the foam. For example, the foam could be exposed to thermal, actinic or ionizing radiation or combinations thereof, subsequent to extrusion to form the cross-bond of the foam. The entanglement could also be done using chemical entanglement methods based on ionic interactions. The invention provides articles containing foam, and a process for preparing such articles, wherein the articles can be designed to exhibit a wide range of properties depending on the final application to which the article is intended. For example, the foam center could be produced only in combination with one or more polymer compositions, e.g., in the form of layers to form multi-layer articles. The ability to combine the foam with additional polymer compositions offers significant design flexibility, since a variety of polymer compositions could be used, including adhesive compositions, additional foam compositions, removable compositions, layers having different mechanical properties , etc. In addition, by careful control from the foaming operation it is possible to produce a foam having a pattern of regions having different densities. Foams can be produced both thin and thick. In addition, both adhesive and non-adhesive foams can be produced. In the latter case, the foam could be combined with one or more separate adhesive compositions to form an adhesive article. In addition, it is possible to prepare foams from a number of different polymer matrices, including polymer matrices which are incompatible with the foam preparation process which is based on polymerization induced by actinic radiation of photopolymerizable compositions containing microspheres. Examples of such polymer matrix compositions include unsaturated thermoplastic elastomers and saturated insoluble thermoplastic acrylate elastomers. Similarly, it is possible to include additives such as ultraviolet absorbing pigments (e.g., black pigments), dyes, and tackifiers that might not be effectively used in the actinic radiation based foaming process. It is also possible, in contrast to the processes of foam-based solvent and based on actinic radiation, to prepare foams that they have a substantially homogeneous distribution of microspheres. In addition, the present expanded foam (i.e., a foam containing microspheres that have at least partially expanded) can have a uniform size distribution of the expanded microspheres from the surface to the center of the foam. That is to say, there is no gradient of sizes of microspheres expanded from the surface to the center of the foam, e.g., as found in expanded foams that are made in a press or in a nozzle. Expanded foams that exhibit such a size distribution gradient of their expanded microspheres may exhibit weaker mechanical properties than foams having a uniform size distribution of the expanded microspheres. In the foaming of these foam compositions long residence times in the stove at high temperature are required, due to the poor thermal conductivity of the foams. Long residence times at high temperatures can lead to degradation of the polymer and vehicle (e.g., release of the protective coating). In addition, poor thermal transfer can also lead to foams that contain non-uniform expansion, causing a density gradient. Such a density gradient can decrease significantly resist and otherwise disadvantageously impact the properties of the foam. The process associated with stove foaming is also complicated and usually requires unique process equipment to eliminate corrugation and large scale ripple of the flat sheet. For a reference of stove foaming see, for example, Handbook of Polymer Foams & Foam Technol ogy, eds: D. Kempner & K.C. Frisch, Hanser Publishers, New York, NY, 1991. Foams with a substantially smooth surface can be produced in a single simple. Therefore, it is not necessary to bond additional layers to the foam to obtain a smooth surface article. Foams of substantially smooth surface are desirable for a number of reasons. For example, when the foam is laminated to another substrate, the substantially smooth surface minimizes entrapment of air between the foam and the substrate. Furthermore, in the case of adhesive foams the substantially smooth surface maximizes contact with a substrate to which the foam is applied, leading to good adhesion. The extrusion process allows the preparation of multi-layer articles, or articles with discrete structures, in a single step. Also, when it is presented foaming during extrusion, it is possible, if desired, to eliminate the post-foam foaming process. In addition, by manipulating the design of the extrusion die (i.e., the shape of the nozzle opening), it is possible to produce foams having a variety of shapes. In addition, the present method could include heating the article after extrusion to cause additional expansion. The additional expansion could be due to the expansion of the microsphere, the activation of a gas production agent, or a combination thereof. It is also possible to prepare "foaming on-site" articles by controlling the temperature of the process during the initial preparation of the foam, so that the expansion of the microspheres is minimized or suppressed. The article can then be placed in a use or application site (e.g., in a hollow area or on an open surface) and heated, or exposed to a high temperature to cause expansion of the microsphere. "Foaming on site" articles can also be prepared by including a gas forming agent in the expandable extrudable composition and driving the extrusion process under insufficient conditions to activate the gas production agent. Subsequent to the foam preparation, the gas production agent can be activated to cause additional foaming. Other features and advantages of the invention will be apparent from the following description of the preferred embodiments thereof, and from the claims.

Brief Description of the Drawings Fig. 1 (a) is a diagram showing the Ra value obtained by profilometry by laser triangulation of the sample described in Example 12. Fig. 1 (b) is a photomicrograph obtained by electron microscopy. Scanning (SEM) of the sample surface described in Example 12. FIG. 2 (a) is a diagram showing the Ra value obtained by profilometry by laser triangulation of the sample described in Example 58. FIG. .2 (b) is an SEM photomicrograph of the surface of the sample described in Example 58. Fig. 3 is a perspective drawing showing a foam having a surface following a pattern. Fig. 4 is a perspective drawing of a article that highlights a foam combined with an additional polymer composition. Fig. 5 is a perspective drawing of an article highlighting a foam combined with two additional polymer compositions. Fig. 6 is a perspective drawing of an article highlighting a foam combined with multiple additional polymer compositions. The Fig. 7 is a schematic drawing of an extrusion process for preparing articles according to the invention. Fig. 8 is a diagram showing the separation force applied in one direction (MD) parallel to the direction of the filament as a displacement function for examples 73, 77 and 78. Fig. 9 is a diagram showing the separation force applied in a direction (CD) perpendicular to the direction of the filament as a displacement function for examples 73, 77 and 78. Fig. 10 is a diagram showing the separation force applied in one direction (MD) parallel to the direction of the filament as a displacement function for examples 72, 79, 80 and 81. Fig. 11 is a diagram showing the force of separation applied in a perpendicular direction (CD) to the direction of the filament as a displacement function for examples 72, 79, 80 and 81. Figs. 12a-12b are SEM microphotographs of cross sections, as seen in the machine direction (MD) and in the transverse direction of the sheet (CD), respectively, of the non-oriented foam described in Example 86. Figs. 12c-12d are SEM microphotographs of cross sections, as seen in the machine direction (MD) and in the transverse direction of the sheet (CD), respectively, of the axially oriented foam described in Example 86. Figs. 13a 13b are SEM microphotographs of cross sections, as seen in the machine direction (MD) and in the transverse direction of the sheet (CD), respectively, of the foam of the polymer mixture described in Example 23.

Detailed Description Article The invention features articles that include a polymer foam that projects a polymer matrix and one or more expandable polymer microspheres. The examination of the foam by electron microscopy reveals that the microstructure of the foam it is characterized by a plurality of elongated polymeric microspheres (with respect to their original size) distributed along the polymer matrix. At least one of the microspheres (and preferably more) is still expandable, i.e., with the application of heat it will expand more without breaking. This can be demonstrated by exposing the foam to heat treatment and comparing the size of the microspheres obtained by electron microscopy to its size of preheating treaty (also obtained by electron microscopy). The foam is further characterized by a surface that is substantially smooth, as defined in the Brief Description of the Invention, above. The results of profilometry by laser triangulation and the electron scanning photomicrographs are shown in Figs. 1 and 2 for representative acrylic foams, having substantially smooth surfaces prepared as described in Examples 12 and 58, respectively, described in more detail below. Each of the microphotographs of Figs. l (b) and 2 (b) include a measuring rod B of 100 micrometers in length. Each of the samples in Figs. l (b) and 2 (b) have been sectioned, with the surface portion that is clear and the section that is sectioned dark The foam could be provided in a variety of ways, including a sheet, bar or cylinder. In addition, the surface of the foam could follow a model. An example of such foam is shown in Fig. 3. The foam 100 is in the form of a sheet having a uniform pattern of protuberances 102, arranged on the surface of the foam. Such articles are prepared by differential foaming, as described below in more detail. The differential foaming process creates protuberances 102 having a density different from the density of the surrounding areas 104. A variety of different polymer resins, as well as mixtures thereof, could be used for polymer matrix as long as the resins are suitable for the extrusion processing of the melt. For example, it may be desirable to mix two or more acrylate polymers having different compositions. A wide range of physical properties of the foam can be obtained by manipulating the type and concentration of the component in the mixture. The particular resin is selected based on the desired properties of the final article containing the foam. The morphology of the immiscible polymer mixture containing the foam matrix can improve the performance of the resulting foam article. The morphology of the mixture may be, for example, spherical, ellipsoidal, fibrillar, co-continuous or combinations thereof. These morphologies can lead to a unique set of properties that are not obtained by a single component in the foam system. Such unique properties could include, for example, anisotropic mechanical properties, improved cohesive force. The morphology (shape and size) of the immiscible polymer mixture can be controlled by the free energy considerations of the polymer system, with respect to the viscosities of the components, and most notably the processing and coating characteristics. By proper control of these variables, the morphology of the foam can be manipulated to provide superior properties of the intended article. Figs. 13a and 13b show SEM photomicrographs of the microstructure of the immiscible polymer mixture of Example 23 (i.e., 80% p of Composition 1 which Fuses by Heat and 20% p of Kraton ™ D1107). The Kraton ™ Dll 07 was stained with Os04 to look like white, allowing this phase to be seen. These Figures show that the Kraton ™ Dll07 phase is a complex morphology consisting of fibrillar microstructures, with sizes of approximately 1 μm. In Fig. 13a, the fibrillar phases of Kraton'IMD1107 are shown in cross section and appear spherical. One class of useful polymers includes acrylate and methacrylate adhesive polymers and copolymers. Such polymers can be formed by polymerizing one or more monomeric acrylic or methacrylic esters of non-tertiary alkyl alcohols, with alkyl groups having from 1 to 20 carbon atoms (e.g., from 3 to 18 carbon atoms). The suitable acrylate monomers include methyl acrylate, ethyl acrylate acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate ciciohexilo acrylate, iso-octyl acrylate, octadecyl acrylate, nonyl acrylate, decyl, and dodecyl acrylate. The corresponding methacrylates are also useful. Also useful are aromatic acrylates and methacrylates, e.g., benzyl acrylate and cyclobenzyl acrylate. Optionally, one or more monoethylenically unsaturated co-monomers could be polymerized with the acrylate or methacrylate monomers; the particular amount of co-monomer is selected based on the desired properties of the polymer. A group of co- Useful monomers include those having a vitreous transition temperature of the homopolymer greater than the glass transition temperature of the acrylate homopolymer. Examples of suitable co-monomers falling within this group include acrylic acid, acrylamide, methacrylamide, substituted acrylamides such as N, N dimethylacrylamide, itaconic acid, methacrylic acid, acrylonitrile, methacrylonitrile, vinyl acetate, N-vinylpyrrolidone, acrylate isobornyl acrylate, cyano ethyl, N-vinylcaprolactam, maleic anhydride, hydroxyalkyl (meth) acrylate, N, N-dimethyl aminoethyl, N, N-diethyl acrylamide, acrylate beta-carboxyethyl, vinyl esters of neodecanoic acid, neopentanoic, 2 -etilhexanoico or propionic (eg, available from Union Carbide Corp. of Danbury, CT under the designation "VYNATES", vinylidene chloride, styrene, vinyl toluene, and alkyl vinyl ethers. a second group of monoethylenically unsaturated co-monomers that may be polymerized with the acrylate and methacrylate monomers includes those having a glass transition temperature of the homopolymer lower than the transition temperature of the acrylate homopolymer. Examples of suitable co-monomers that fall within this class include ethyloxyethoxy ethyl acrylate (Tg = -71 ° C) and a methoxypolyethylene glycol 400 acrylate (Tg = -65 ° C, available from Shin Nakamura Chemical Co., Ltd. under the designation "NK Ester AM-90G"). A second class of polymers useful for the polymer matrix of the foam include insoluble acrylate polymers. Examples include semicrystalline polymer resins such as polyolefins and polyolefin copolymers (eg, based on monomers having 2 to 8 carbon atoms, such as low density polyethylene, high density polyethylene, polypropylene, ethylene-propylene copolymers, etc.), polyesters and co-polyesters, polyamides and co-polyamides, fluorinated homopolymers and copolymers, polyalkylene oxides (eg, polyethylene oxide and polypropylene oxide), polyvinyl alcohol, ionomers (eg, ethylene-methacrylic acid copolymers neutralized with base), and cellulose acetate. Other examples of insoluble acrylate polymers include amorphous polymers having a solubility parameter (as measured according to the technique of Fedor) less than 8 or greater than 11 such as polyacrylonitrile, polyvinyl chloride, thermoplastic polyurethanes, thermoplastic epoxies, polycarbonate , amorphous polyesters, amorphous polyamides, copolymers ABS, mixtures of polyphenylene oxide, ionomers (e.g., ethylene-methacrylic acid copolymers neutralized with salt), fluorinated elastomers and polydimethyl siloxane.

A third class of polymers useful for the polymer matrix of the foam includes elastomers containing groups that are activated by ultraviolet radiation. Examples include polybutadiene, polyisoprene, polychloroprene, random and block copolymers of styrene and dienes (e.g., SBR), and ethylene-propylene-diene monomer rubber. A fourth class of polymers useful for the polymer matrix of the foam includes pressure sensitive adhesives and melts by heating, prepared from non-photopolymerizable monomers. Such polymers can be adhesive polymers (i.e., polymers that are inherently adhesive), or polymers that are not inherently adhesive but are capable of forming adhesive compositions when compounded with tackifiers. Specific examples include poly-alpha-olefins (eg, polyoctene, polyhexene, and atactic polypropylene), block copolymer-based adhesives (eg, di-block, tri-block, star block and combinations thereof), natural rubbers and Synthetic, silicone adhesives, ethylene-vinyl acetate, and adhesive mixtures epoxy-containing structural elements (e.g., epoxy-acrylate and epoxy-polyester mixtures). The expandable microspheres highlight a flexible, thermoplastic, polymeric coating, and a center that includes a liquid and / or gas that expands when heated. Preferably, the core material is an organic substance having a boiling point lower than the softening temperature of the polymeric coating. Examples of suitable core materials include propane, butane, pentane, isobutane, neopentane, and combinations thereof. The selection of the thermoplastic resin of the polymeric coating influences the mechanical properties of the foam. Therefore, the properties of the mixture could be adjusted by appropriate selection of the microsphere, or by using mixtures of different types of microspheres. For example, resins containing acrylonitrile are useful when high tensile and cohesive forces are desired, particularly when the content of acrylonitrile is at least 50% by weight of the resin, more preferably at least 60% by weight, and further preferably at least 70% by weight. In general, both tensile and cohesive forces increase with increasing acrylonitrile content. In some In some cases, it is possible to prepare foams having tensile and cohesive force higher than the polymer matrix alone, even though the foam has a density lower than the matrix. This provides the ability to prepare items of high effort and low density. Examples of suitable thermoplastic resins that could be used as the coating include esters of acrylic and methacrylic acid such as polyacrylate; arylate-acrylonitrile copolymer; and methacrylate-acrylic acid copolymer. Polymers containing vinylidene chloride such as vinylidene chloride copolymer, methacrylate, vinylidene chloride-acrylonitrile copolymer, acrylonitrile-vinylidene chloride-methacrylonitrile-methyl acrylate copolymer, and acrylonitrile-vinylidene chloride-copolymer could also be used. methacrylonitrile-methyl methacrylate, but are not preferred when high stress is desired. In general, when high stress is desired, the coating of the sphere preferably has not more than 20% by weight of vinylidene chloride, more preferably not more than 15% by weight of vinylidene chloride. Even more preferred for high stress applications are microspheres that do not have essentially vinylidene chloride units.

Examples of suitable commercially available expandable polymeric microspheres include those available from Pierce Stevens (Buffalo, NY) under the designations "F30D", F80SD "and" F100D. "Expandable polymeric microspheres available from Akzo-Nobel under the designations" Expancel "are also suitable. 551"," Expancel 461"and" Expancel 091. "Each of these microspheres characterizes an acrylonitrile-containing coating In addition, the F80SD, F100D and Expancel 091 microspheres have essentially vinylidene chloride units in the coating.

The amount of expandable microspheres is selected based on the desired properties of the foam product. In general, at higher concentration of microspheres lower density of foam. In general, the amount of microspheres is in the range of about 0.1 parts by weight to about 50 parts by weight (based on 100 parts of polymer resin), more preferably from about 0.5 parts by weight to about 20 parts by weight. The foam could also include a number of other additives. Examples of suitable additives include adherents (e.g., resin esters, terpenes, phenols and aliphatics, aromatics or mixtures of resins of synthetic aliphatic and aromatic hydrocarbons), plasticizers, pigments, dyes, non-expandable polymer or glass microspheres, reinforcing agents, hydrophobic or hydrophilic silica, calcium carbonate, curing agents, fire retardants, antioxidants, finely ground polymeric particles such as polyester, nylon or polypropylene, stabilizers, and combinations thereof. Chemical agents for gas production could also be added. The agents are added in sufficient amounts to obtain the desired final properties. The properties of the article could be adjusted by combining one or more polymer compositions with the foam. These additional compositions could take different forms, including layers, strips, etc. both foamed and non-foamed compositions could be used. A composition could be attached directly to the foam or indirectly, e.g., by separate adhesives. In some embodiments, the additional polymer composition is bonded to the foam so that it can be moved; such compositions can subsequently be separated from the foam. Examples of articles of comptations characteristic of a foam and one or more compositions of additional polymer are shown in Figs. 4-6. Referring to Fig. 4, an article 200 is shown which highlights a plurality of foam strips 202 arranged in a pattern and combined within a separate polymer layer 204. The density of the strips 202 is different from the density of the layer. of polymer 204 surrounding the strips. Fig. 5 depicts another article 300 in which a plurality of foam strips 302 are arranged in a pattern and combined within a separate polymer layer 304. Layer 304, in turn, is joined to another polymer layer 306 on its opposite side. The density of the strips 302 is different from the density of the layer 304 surrounding the strips. FIG. 6 depicts yet another article 400 in which a plurality of foam strips 402 are immersed within a multilayer structure that delineates the polymer layers 404, 406 and 408. The density of the strips 402 is different from the density of the polymer. Layers 404, 406 and 408. Preferably, the additional polymer compositions are attached to the center of the foam by co-extruding the composition containing microspheres capable of extruding with one or more polymer compositions capable of extrusion, as described with more detail later. The number and type of polymer compositions is selected based on the properties of the final foam-containing article. For example, in the case of non-adhesive foam centers, it may be desirable to combine the center with one or more adhesive polymer compositions to form an adhesive article. Other examples of polymer compositions prepared by coextrusion include relatively high modulus polymer compositions for reinforcing the article (semi-crystalline polymers such as polyamides and polyesters), relatively low modulus polymer compositions to increase the flexibility of the article (eg , plasticized polyvinyl chloride), and additional foam compositions.

Extrusion Process Referring to Fig. 7, an extrusion process is shown to prepare an article that includes a polymer foam that conceives a polymer matrix and one or more expandable polymer microspheres. According to the process, the polymer resin is initially fed into a first extruder 10 (typically a screw extruder) which softens and grinds the resin into small particles suitable for extrusion. The polymer resin will eventually form the polymer matrix of the foam. The polymer resin could be added to the extruder 10 in any convenient way, including particles, beads, packages, strips and yarns. Then, the resin particles and all the additives except the expandable microspheres are fed to a second extruder 12 (e.g., a one or two screw extruder) at a point immediately before the mixing section of the extruder. Once combined, the resin particles and additives are fed to the mixing zone of the extruder 12 where they mix well. The mixing conditions (e.g., screw speed, screw length and temperature) are selected to obtain optimum mixing. Preferably, the mixing is carried out at an insufficient temperature to cause expansion of the microsphere. It is also possible to use temperatures in excess of the expansion temperature of the microsphere, in this case the temperature is decreased after mixing and before adding the microspheres. When mixing is not needed, e.g., when there are no additives, the mixing step could be omitted. In addition, when the polymer resin is already in a form suitable for extrusion, the first one could be omitted Extrusion step and add the resin directly to the extruder 12. Once the resin particles and additives have been properly mixed, the expandable polymeric microspheres are added to the resulting mixture and the melt is mixed to form an expandable extrudable composition. . The purpose of the mixing step of the melt is to prepare an expandable extrudable composition in which the expandable polymer microspheres and other additives, to the present degree, they are distributed substantially homogeneously throughout the molten polymer resin. Typically, the mixing operation of the melt uses a mixing block to obtain adequate mixing, although simple transport elements could also be used. The temperature, pressure, shear rate and mixing time employed during the mixing of the melt are selected to prepare this expandable extrudable composition without causing the microspheres to expand or break.; once broken, the microspheres are not able to expand to create a foam. The specific temperatures, pressures, cutting ratios and mixing times are selected based on the composition particular that is going to be processed. After mixing the melt, the expandable extrudable composition is fed to the extrusion die 14 (eg, a contact or jet nozzle) through a length of the transfer tube 18 using a gear pump 16 which It acts as a valve to control the pressure of the nozzle and thus prevent the premature expansion of the microspheres. The temperature inside the nozzle 14 is preferably maintained at substantially the same temperature as the temperature inside the transfer tube 18, and is selected such that it is at or above the temperature required to cause expansion of the expandable microspheres. However, although the temperature inside the tube 18 is high enough to cause expansion of the microsphere, the relatively high pressure inside the transfer tube prevents them from expanding. However, once the composition enters the nozzle 14 the pressure drops. The pressure drop, coupled with the heat transfer from the nozzle, causes the microspheres to expand and the composition to foam inside the nozzle. The pressure inside the nozzle continues to fall as the composition reaches the outlet, contributing more to the expansion of the microspheres inside the nozzle. The flow rate of the polymer through the extruder and the outlet opening of the nozzle is maintained in such a way that the polymer composition is processed through the nozzle, the pressure in the nozzle cavity remains sufficiently low that the expansion of the expandable microspheres before the polymer composition reaches the outlet opening of the nozzle. The shape of the foam is dictated by the shape of the outlet opening of the nozzle 14. Although a variety of shapes could be produced, the foam typically occurs in the form of a continuous or discontinuous sheet. The extrusion nozzle could be a jet nozzle, contact nozzle, profile nozzle, annular nozzle, or a cast nozzle, for example, as described in Extrusi ón Di es: Desi gn & 'Computational Engineering, Walter Michaelis, Hanser Publishers, New York, NY, 1984, which is hereby incorporated by reference in its entirety. It may be preferable for most, if not all, of the expandable microspheres to partially or fully expand before the polymer composition leaves the nozzle. Causing the expansion of expandable polymer microspheres before the composition leaves the nozzle, the resulting extruded foam can be produced within narrower densities of density and thickness (caliper). A narrower tolerance is defined as the density deviation or thickness in the machine (or longitudinal) and transverse direction of the sheet (or transverse) of average density or thickness (s / x), respectively. The s / x obtained according to the present invention can be less than about 0.2, less than about 0.1, less than about 0.05, and even less than about 0.025. Without any intention to be limited, the narrower tolerances obtainable according to the present invention are evidenced by the following examples. As shown in Fig. 7, the foam could optionally be combined with a protective coating 20, supplied "from the feed roller 22. Suitable materials for the protective coating 20 include silicone release protective coatings, polyester films ( eg, polyethylene terephthalate films), and polyolefin films (eg, polyethylene films) The protective coating is then laminated together between a pair of clamping rollers 24. After the lamination or after it is extruded but before lamination, the foam is optionally exposed to radiation from an electron beam source 26 to form cross-links in the foam; other sources of radiation (e.g., ion beam, thermal and ultraviolet radiation) could also be used. The entanglement improves the cohesive strength of the foam. After exposure, the sheet is wound on a roll of roll 28. If desired, the smoothness of one or both surfaces can be increased by using a clamping roll to press the foam against a cooling roll after the foam comes out of the roll. the nozzle 14. It is also possible to stamp a pattern on one or both surfaces of the foam by contacting the foam with a roller having a pattern after it leaves the nozzle 14, using conventional microreplication techniques, such as, for example , those described in the US Patents Nos. 5,897,930 (Calhoun et al.), 5,650,215 (Mazurek et al.) And PCT Patent Publication No. WO 98 / 29516A (Calhoun et al.), Which are incorporated herein by reference. The replication pattern can be chosen from a wide range of geometric shapes and sizes, depending on the desired use of the foam. The surface substantially Smooth extruded foam allows micro-replication of the foam surface to a degree of precision and accuracy higher. Such high-quality replication of the present foam surface is also facilitated by the ability of the foam to resist being compressed by the pressure exerted on the foam during the microreplication process. Microreplication techniques can be used without significantly compressing the foam because the foam includes expandable microspheres that do not collapse under the pressure of the microreplication roll, compared to foaming agents such as gas. The extrusion process could be used to prepare "on-site foam" articles. Such articles find application, for example, as seals or other items that seal a space, vibration dampening articles, tape backings, retroreflective sheet backings, anti-fatigue grids, abrasive article backings, high pavement marker adhesive pads , etc. The foaming articles on the site could be prepared carefully by controlling the pressure and temperature inside the nozzle 14 and transfer tube 18, so that the expansion of Microspheres do not present to any appreciable degree. The resulting article is then placed in a desired area, e.g., a hollow area or open surface and heated to, or exposed to, a temperature high enough to cause expansion of the microsphere. Foaming articles on the site can also be prepared by incorporating a chemical gas production agent such as 4,4'-oxybis (benzenesulfonylhydrazide) into the expandable extrudable composition. The gas production agent can be activated subsequent to the extrusion to cause additional expansion, thus allowing the article to fill the area in which it is placed.

The extrusion process can also be used to prepare foams that follow a pattern that have areas of different densities. For example, downstream of the point at which the article exits the nozzle, the article can be selectively heated, e.g., using a roller having an infrared pattern or mask, to cause expansion of the microsphere in designated areas of the article. The foam could also be combined with one or more additional polymer compositions, e.g., in the form of layers, strips, bars, etc., preferably co-extruding additional extrudable polymer compositions with the extrudable compositions containing microspheres. Fig. 7 illustrates a preferred co-extrusion process for producing an article that delineates a foam between a pair of polymer layers. As shown in Fig. 7, the polymer resin is optionally added to a first extruder 30 (e.g., a screw extruder) where the melt melts and melts. The mixed molten resin is then fed to a second extruder 32 (e.g., a one or two screw extruder) where it is mixed with any desired additive. The resultant extrudable composition is then fed to the appropriate chambers of the nozzle 14 through the transfer tube 34, using a gear pump 36. The resulting article is a three-layer article that characterizes a foam center having a polymer layer on each of its main surfaces. It is possible to conduct the co-extrusion process in such a way that a two-layer article is produced, or in such a way that articles have more than three layers (eg, 10-100 layers or more), equipping the nozzle 14 with an appropriate power block, or using a multi-blade or multi-distributor nozzle.

Clamping layers, primer layers or barrier layers can also be included to increase interlayer adhesion or reduce diffusion through the construction. further, interlayer adhesion of a construction having multiple layers (e.g., A / B) of different compositions can also be improved by mixing a fraction of material A in layer B (A / AB). Depending on the degree of interlayer adhesion, the concentration of A in layer B will be dictated. Multilayer foam articles can also be prepared by laminating additional polymer layers to the center of the foam, or to any layer of co-extruded polymer after the article comes out of the nozzle 14. Other techniques that may be used include coating the extruded foam (ie, extruded) with strips or other discrete structures). Post-processing techniques, which could include lamination, embossing, extrusion coating, solvent coating or orientation, could be performed on the foam to impart superior properties. The foams could be oriented uni-axially or multi-axially (i.e., stretched in one or more directions) to produce foam structures containing microvoids between or a separation of the foam matrix and expandable microspheres (See Examples 85-92). Figs. 12a-12d show SEM microphotographs of the foam microstructure of Example 86, before (Figs 12a and 12b) and after (Figs 12c and 12d) of the uniaxial orientation. Figs. 12a and 12c are views of the cross section of the foam microstructure as seen in the machine direction (MD). That is, for Figs. 12a and 12c, the foam was sectioned perpendicular to the flow direction of the foam as it exits the nozzle and is seen in the direction of flow. Figs. 12b and 12d are cross-sectional views of the foam microstructure as seen in the transverse direction of the sheet (CD) That is, for Figs. 12b and 12d, the foam was sectioned parallel to the flow direction of the foam as it exits the nozzle and is viewed in the direction perpendicular to the direction of flow. The selection of the foam matrix, type of microsphere susceptible to extrusion / concentration and orientation conditions can affect the ability to produce micro-hollow foam materials. Orientation conditions include temperature, direction (s) of stretch, stretch ratio, and degree of stretch (i.e., orientation ratio). It is believed that the interfacial adhesion between the foam matrix and the microspheres expandable should be such as to allow at least some disbonding to occur around the microspheres in the stretch (i.e., orientation). It is also believed that poor interfacial adhesion may be preferred. In addition, it has been found desirable for the foam matrix capable of withstanding relatively high elongation (e.g., at least 100%). The orientation of the foam samples can cause a reduction in foam density (e.g., up to about 50%) due to the formation of microvoids between the foam matrix and the microspheres formed during orientation. The microvoids can remain after the stretching process (orientation) or they can disappear (i.e., collapse but the interface remains unbound). In addition, delamination between the foam matrix and the microspheres, with or without a noticeable reduction in density, can result in a significant alteration of the mechanical properties of the foam (eg, increased flexibility, reduction of reinforcement, an increase in the softening of the foam, etc.). Depending on the final application of the foam, the material selection and orientation conditions can be selected to generate desired properties. It may be desirable for the polymer composition susceptible to extrude that can be interlaced. The entanglement can improve the cohesive strength of the resulting foam. It may be desirable that the interlacing of the extrudable polymer starts at least between the mixing step of the melt and the exit of the polymer through the opening of the nozzle, during or after foaming, such as by the use of energy. thermal (ie, heat-activated curing). Alternatively or additionally, the extrudable polymer composition may intertwine upon exit from the nozzle such as, for example, by exposure to thermal, actinic or ionizing radiation or combinations thereof. The entanglement could be done using chemical entanglement methods based on ionic interactions. The degree of entanglement can be controlled to influence the properties of the finished foam article. If the extruded polymer is laminated, as described herein, the extruded polymer can be entangled before or after lamination. Suitable thermal interlacing agents for the foam may include epoxies and amines. Preferably, the concentrations are sufficiently low to avoid excessive entanglement or gel formation before the composition leaves the nozzle.

IZfiS. Articles that contain foam are useful in a variety of applications that include, for example and without form of limitation, aerospace, automotive and medical applications. The properties of the articles are designed to meet the demands of the desired applications. Specific examples of applications include vibration damping articles, medical bandages, tape backings, retroreflective sheet backings, anti-fatigue grids, abrasive article backings, raised pavement marker pads, gaskets and sealants. The invention will now be described more by way of the following examples.

EXAMPLES Test Methods Surface Roughness The topology of the surface as a function of displacement was measured using a Laser Triangulation Profiler (Cyberscan 200, available from Cyberoptics of Minneapolis, MN). All measurements were collected at room temperature using a HeNe laser (654 nm) with a resolution of the dot range of 1 micrometer (PSR-40). The laser was programmed to move through the sample in discrete 25 micrometer jumps with a total of 50 jumps (total length = 1250 micrometers). The sample size measured 1250 x 1250 micrometers. The roughness results were adjusted by subtracting a linear regression adjustment from the results and placing the average at zero. The roughness of the surface, Ra, was calculated using the following relationship: where Ra is the roughness of the surface, Lm is the length of the total displacement, and z is the height in a displacement of x.

Adhesion at 90 ° A sheet of pressure-sensitive adhesive foam is laminated to an anodized aluminum sheet 0.127 mm thick. A strip of tape measuring 1.27 cm by 11.4 cm is cut from the sheet and applied to a metal substrate that was painted with an automotive basecoat / clearcoat paint composition (RK-7072 from DuPont Co.) The strip Rolls up after using four total steps, using a 6.8 kg metal roller. The sample is aged with one of the following conditions before testing: 1 hour at room temperature (22 ° C) 3 days at room temperature (22 ° C) 7 days at 70 ° C 5 days at 100 ° C and 100% Moisture After aging, the panel is mounted on an Instron ™ Voltage Tester so that the belt pulls at a 90 degree angle at a speed of 30.5 cm per minute. The results are determined in pounds by 0.5 inches, and converted to Newtons per decimeter (N / dm).

T-Adhesion This test is performed according to ASTM D3330-87 except as specified. A strip of foam measuring 11.43 cm by 1.27 cm wide is laminated between two strips of anodized aluminum (10.16 cm long by 1.59 cm wide by 0.127 mm thick). The laminate test sample is conditioned for at least 1 hour at room temperature (22 ° C), and then tested for cohesive strength using an Instron ™ Voltage Tester at 180 ° peel and a crosshead speed of 77.5. cm (30.48 inches) per minute. The results of the Test are recorded in pounds by 1/2 inch wide and results are converted to newtons / decimeter (N / dm).

Stress and Elongation This test is performed according to ASTM D412-92 except as specified. A sample of the foam is cut into a "dog bone" shape that has a width of 0.635 mm in the middle portion. The ends of the sample are fixed in an Instron Stress Tester and pulled at a crosshead speed of 50.8 cm per minute. The test measures the peak effort (in pounds per square inch and converted to kilopascal (kPa)), the amount of elongation or peak stretch (in% of the original length), and the peak energy (in feet pounds and became to joules (J).

Static Cutting Effort A 2.54 cm by 2.54 cm strip of pressure-sensitive adhesive foam tape is laminated to an anodized aluminum panel 0.51 mm thick measuring approximately 2.54 cm by 5.08 cm. A second panel of the same size is placed on the tape so that there is an overlap of 2.54 cm, and the ends of the panels extend opposite each other. The sample is then roll with a 6.8 kg metal roller, so that the total contact area of the sample for the panel is 2.54 cm by 2.54 cm. The prepared panel is conditioned at room temperature, i.e., approximately 22 ° C for at least 1 hour. The panel is then hung in an oven at 70 ° C and placed 2 degrees from the vertical to avoid a peeling type failure. A weight of 750 grams is hung at the free end of the sample. The time required for the sample with the weight to fall from the panel is recorded in minutes. If there is no failure in 10,000 minutes, the test is discontinued and the results are recorded as 10,000+ minutes.

Gumming 1 Heat Melting A pressure sensitive adhesive composition was prepared by mixing 90 parts of IOA (isooctyl acrylate), 10 parts of AA (acrylic acid), 0.15 parts of 2,2 dimethoxy-2-phenylacetophenone (Irgacure ™ 651 available in Ciba Geigy) and 0.3 parts of IOTG (isooctyl thioglycolate). The composition was placed in packs measuring approximately 10 cm by 5 cm by 0.5 cm thick, packages as described in U.S. Pat. No. 5,804,610, filed on August 28, 1997, published on September 8, 1998 and Incorporated here by reference. The packing film was 0.0635 thick ethylene vinyl acetate copolymer (VA-24 Film available from CT Film d Dallas, TX). The packages were immersed in a water bath and at the same time exposed to ultraviolet radiation at an intensity of 3.5 iliWatts per square centimeter and a total energy of 1627 milliJoules per square centimeter that was measured in NISt units to form a sensitive adhesive to the packed pressure. The resulting adhesive had an IV (intrinsic viscosity) of approximately 1.1 deciliters / gram, MW of 5.6 x 105 g / mol and Mn of 1.4 x 105 g / mol.

Go position 2 that melts by heat A packaged adhesive was prepared following the procedure for Composition 1, which melts by heat, except that 97 parts of IOA and 3 parts of AA were used.

Composition 3 that Melts from Heat A packaged adhesive was prepared following the procedure for Composition 1 that Melts from Heat, except that 80 parts of IOA and 20 parts of AA were used.

Composition 4 is Heat Melt A Heat Melting composition of pressure sensitive adhesive having 96 parts of IOA and 4 parts of methacrylic acid was prepared following the procedure described in U.S. Pat. No. 4,833,179 (Young et al.) Incorporated herein in its entirety by reference.

Heat-melting Composition 5 A packaged adhesive was prepared following the procedure for Heat Melting Composition 1, except that 46.25 parts of isooctyl acrylate, 46.25 parts of n-butyl acrylate (nBA), and 7.5 parts of acrylic acid The packaged adhesives were then combined in a two-screw extruder with 17% Escorezm180 adhesive (available from Exxon Chemical Corp.) to form Composition 5, which melts by heat.

Heat Melting Composition 6 A hot melt adhesive composition was prepared following the procedure for Heat Melting Composition 5, except that the packaged adhesive composition was 45 parts IOA, 45 parts nBA, and were used 10 parts of AA.

Composition 7 that Fuses by Heat A Composition that Melts by Heat of adhesive was prepared following the procedure for Composition 1 that Melts by Heat, except that the composition in the packages also included 0.25 parts of acryloxybenzophenone per one hundred parts of acrylate.

Heat Smelting Composition 8 A Heat Smelting composition having 90 parts of IOA and 10 parts of AA was prepared following the procedure of Example 1 of U.S. Pat. No. 5,637,646 (Ellis), incorporated herein in its entirety by reference.

Composition 9 that Melts from Heat A Composition that Melts from Heat that had 95 parts of IOA and 5 parts of AA was prepared following the procedure for "Composition 1 that Melts from Heat.

Composition 10 Dream Melts by Heat A Heat Melting composition having 90 parts of 2-ethylhexyl acrylate and 10 parts of AA was prepared following the procedure for Composition 1, which melts by heat.

Extrusion Process The packaged heat fusion composition was fed to a 51 mm screw extruder (Bonnot) and combined. The temperatures in the extruder and the flexible hose at the outlet end of the extruder were all set at 93.3 ° C and the flow rate was controlled with a Zenith gear pump. The adhesive The combined feed was then fed to a 30mm co-rotating twin screw extruder with three additive ports (Werner Pfleider) operating at a screw speed of 200 rpm with a flow rate of approximately 4.5 kilograms / hour (10 pounds / hour). The temperature for all zones in the two-screw extruder was established at the specific temperatures indicated in the specific examples. The expandable polymeric microspheres were added downstream at the third feed port approximately three quarters below the barrel of the extruder. The temperatures of the hose and the nozzle were set at the temperatures indicated for the specific examples. The extrudate was pumped to a 15.24 cm jet nozzle that was shimmed to a thickness of 1016 mm. The resulting foam sheets had a thickness of approximately 1 mm. The extruded sheet was molded on a cooling roller that was set at 7.2 ° C, cooled to approximately 25 ° C, and then transferred to a 0.127 mm thick polyethylene protective coating.

EXAMPLES 1-5 Foam sheets of Examples 1-5 were prepared using Composition 1 which Melts by Heat in the process described above, using varying amounts of expandable polymeric microspheres having a coating composition containing acrylonitrile and methacrylonitrile (F100D available at Pierce Stevens, Buffalo, NY). The amounts of microspheres in parts by weight per 100 parts of adhesive compositions (EMS-pph) are shown in Table 1. The extruder temperatures were set at 93.3 ° C, and the temperatures of the hose and the nozzle were set at 193.3 ° C. After enfolding, the extruded foam sheets were transferred to a 0.127 mm thick polyethylene film and interlaced using an electron beam processing unit (ESI Electro Curtain) operating at an acceleration voltage of 300 keV and a speed of 6.1 meters per minute. The measured dose of e-beam was 4 megaRads (mrads). All the foams were sticky. The sheets of foam in the Examples 1, 2, 4 and 5 were joined (e.g., laminated) to a double layer film adhesive using pressure on a clamping roll to make a tape. The first layer of the film adhesive was prepared by dissolving 10 parts of polyamide (Macromelt 6240 from Henkel) in a solvent mixture of 50 parts of isopropanol and 50 parts of n-propanol, coating the solution in a protective release coating, and drying in a stove at 121 ° C for 15 minutes. The second layer of the film adhesive was a solvent-based pressure sensitive adhesive, having a composition of 65 parts of IOA, 30 parts of methyl acrylate, and 5 parts of AA made according to the method described in Re24906 (Ulrich ), incorporated here by reference. A protective release liner was then placed in the solvent-based pressure sensitive adhesive, and the polyamide side of the film adhesive was laminated "by pressure for the foam." The tapes were tested for 90 ° adhesiveness, adhesiveness T , stress and elongation, and static stress The test results and foam densities for all the examples are shown in Table 1.

Example 6 A foam sheet was prepared following the procedure for Example 3, except that the extruder temperatures were set at 121 ° C, and the temperatures of the hose and nozzle were set at 177 ° C. After cooling, the foam was entangled with a dose of 8 mrads.

Examples 7-9 Foam tapes coated with pressure sensitive adhesive were prepared following the procedure for Example 1, except that the extruder temperatures were set at 121 ° C and the amounts of microspheres were 6, 8 and 10 pph for the Examples 7, 8 and 9 respectively.

Examples 10-13 The foam sheets were prepared following the procedure for Example 3, except that the extruder temperatures were set at 82 ° C, and the hose and nozzle temperatures were set at 104 ° C, and according to to the conditions specified below. For Example 10, 2 pph of expandable polymeric microspheres (F50D available from Pierce Stevens) were used and the extruder flow rate was 4. 08 kg per hour. For Example 11, 2 pph of expandable polymeric microspheres having a coating composition containing acrylonitrile, vinylidene chloride and methymethacrylate (Encapsulated Microspheres of Expancel 461 available from Akzo Nobel) were used. For Example 12, 2 pph of expandable polymeric microspheres having a coating composition containing acrylonitrile, methacrylonitrile and methyl methacrylate (Expancel 091 available from Akzo Nobel) were used, the extruder temperatures were set at 93.9 ° C., and the temperatures of the hose and nozzle were set at 193.3 ° C. The foam was measured for main headroom. The roughness of the surface (Ra) was 14 micrometers, and a portion of the foam is shown in Figure 1 (a) and Kb). Example 13 was prepared following the procedure of Example 12, except that 2 pph of expandable polymeric microspheres having a coating containing acrylonitrile, methacrylonitrile and methyl methacrylate (F80SD microspheres available from Pierce Stevens) were used and the extruder temperatures were established. at 93.3 ° C. Additionally, 0.15 parts in weight per hundred parts of 2,4-bis (trichloromethyl) -6,4-methoxyphenyl) -s-thiazine acrylate were mixed with the expandable polymeric microspheres and added to the extruder. The resulting foam was entangled with a mercury vapor lamp with 500 milliJoules / square centimeter of energy (NIST units). The foam had a surface roughness (Ra) of 33 micrometers.

E ploses 14-15 Pressure-sensitive adhesive foam tapes were prepared following the procedures for Examples 2 and 3, respectively, except that the extruder temperatures were set at 121 ° C, and 10% by weight of a tackifier was added. cast (Escorez ™ 180 obtained from Exxon Chemical Co.) in the first port in the barrel of the extruder. The flow rate of the extrudate was 4.08 kg per hour of combined acrylate and 0.45 kg per hour of adherent. The cold foam was intertwined with a dose of 8 mrads.

Example 16 A pressure-sensitive adhesive foam tape was prepared following the procedure for Example 2, except that 0.2 parts per hundred parts of acrylate of a gas production chemical (4,4 'oxybis (benzenesulfonylhydrazide) obtained as Celogen OT in Uniroyal Chemical Co.) was mixed with the microspheres and added to the extruder.

Example 17 A pressure-sensitive adhesive foam tape was prepared following the procedure for Example 2, except that the extruder temperatures were maintained at 110 ° C. A mixture of 50 parts by weight of F80SD expandable polymeric microspheres and 50 parts of a mixed gas production chemical (BIH, a mixture of 85% sodium bicarbonate and 15% citric acid, available from Boehringer-Ingelheim) added at a rate of 2 pph. The extruder flow rate was 3.54 kg per hour. The resulting foam was entangled as in Example 1 at a dose of 6 mrads.

Example 18 A foam sheet was prepared by following the procedure for Example 3, except that 1.6 pph of expandable polymeric microspheres F80SD as well as 0.4 pph of glass bubbles (S-32 available in Minnesota Mining & Composition 4 that Melts by Heat was fed directly into the extruder of two screws, and 4 pph of expandable polymeric microspheres F80SD were used.

Examples 22-27 Pressure sensitive adhesive foam sheets having the adhesive film of Example 2 were prepared following the procedure of Example 2, except that F80 expandable polymer microspheres were used instead of F100D, and the extruder temperatures were set at 104 ° C. Additives were also fed to the first port of the extruder in the type and amount for each example as follows: Example 22 - 10% by weight of the polyethylene extrudate (Engage ™ 8200 available from Dow Chemical Co.) was added to the extruder at a rate of 0.45 kg / hr in the first port. Example 23 - 20% by weight of the styrene-isoprene-styrene block copolymer extrudate (Kraton ™ D1107 available from Shell Chemical Co.) was added to the extruder at a rate of 0.9 kg / hr. The foam had a surface roughness (Ra) of 25 microns on one main surface and 19 microns on the other main surface.

Manufacturing Company). The microspheres and glass bubbles were mixed together before adding to the extruder. The foam had a roughness (Ra) of 24 microns on one main surface and 21 microns on the other main surface.

EXAMPLES 19-20 Foam sheets were prepared by following the above extrusion process, using Composition 3 which melts by heat and with 2 pph of expandable polymeric microspheres (F80SD). The extruder temperatures were set at 110 ° C, and the temperatures of the hose and nozzle were set at 193 ° C. The feed rate of the extruder was 3.58 kg / hr. Example 20 also includes a plasticizer (Santicizer 141 available from Monsanto) and which was fed into the extruder at 0.36 / hr. The foams were entangled following the procedure of Example 1. Example 19 was further laminated to the adhesive film of Example 1.

Example 21 A foam sheet was prepared following the procedure for Example 20, except that the Example 24 - Same as Example 23, except that no other adhesive was laminated to the foam. Example 25 - 25% by weight of the polyester extrudate (Dynapol'm1402 available from Huis America) was added to the extruder at a rate of 1.13 kg / hr. Example 26 - Same as Example 25, except that no other adhesive was laminated to the foam.

Example 27 A sheet of pressure-sensitive adhesive foam was prepared using Composition 7 which Melts by Heat and 2 pph of expandable polymeric microspheres (F80SD). The extruder temperatures were set at 104 ° C, and the temperatures of the hose and nozzle were set at 193 ° C. The resulting foam was cooled and entangled with an electron beam dose of 4 mrads at an acceleration voltage of 300 kilo-electron volts (Kevj.

Example 28 A single layer foam sheet was prepared following the procedure for Example 3, except that a 25.4 cm wide blade coextrusion nozzle was used instead of a jet nozzle, the temperature of the extruder was set to 104. ° C, and microspheres were used Expandable polymeric F80SD. There was no material flow through the external blades. The cold foam was entangled with an electron beam dose of 6 mrads at an acceleration voltage of 300 Kev.

EXAMPLE 29 A foam sheet was prepared following the procedure of Example 28, except that Heat-Fusing Composition 2 was used.

Example 30 A foam sheet was prepared following the procedure of Example 29, except that expandable polymeric microspheres F100D were used.

EXAMPLES 31-33 Foam sheets were prepared following the procedure of Example 28, except that the outer blades were opened and a layer of Heat Smelting Composition 5 was coextruded into each major surface of the foam sheet. The thickness of the layer of Composition 3 was 50 micrometers, 100 micrometers and 150 micrometers (i.e., 2 mils, 4 mils and 6 mils) for examples 31, 32 and 33 respectively. The temperatures of the extruder and the hose for the Additional layers were set at 177 ° C. The foam sheet of Example 31 had a surface roughness (Ra) of 24 microns.

Example 34 A foam sheet was prepared following the procedure for Example 31, except that the extruder temperatures were set at 93.3 ° C, and the hose and nozzle temperatures were set at 171 ° C, and an adherent was added . The feed rate of the extruder was 4.08 kg / hr for Composition 1 and 0.45 kg / hr for an adherent (Escorez ™ 180). Composition 5 that Melts by Heat was coextruded to a thickness of 100 microns in each major surface of the foam. The co-extruded compound was entangled with an electron beam at an acceleration voltage of 275 Kev and a dose of 8 mrads.

EXAMPLE 35 A foam sheet was prepared following the procedure for Example 34, except that instead of adherent, low density polyethylene was used.

(Dowlex ™ 2571 available from Dow Chemical Co.) was added to the extruder at a feed rate of 1.36. kg / hr and Composition 1 was fed at a rate of 3.18 kg / hr. Composition 6 which melts by heat was coextruded to a thickness of 50 micrometers in each major surface of the foam. The resulting co-extruded compound was cooled and entangled with an electron beam at an acceleration voltage of 250 Kev and a dose of 6 mrads.

Examples 36-37 Pressure-sensitive adhesive foam sheets were prepared following the procedure for Example 31, except that the microspheres used were a 50/50 mixture of F80SD and F100D microspheres and the extruder temperatures were set at 93 ° C, and the temperatures of the hose and the nozzle were set at 171 ° C. Example 36 was entangled with an acceleration voltage for e-beam of 250 Kev and a dose of 6 mrads. The outer blades of the nozzle were opened for Example 37 and the foam was co-extruded with 0.15 mm thick layer of low density polyethylene (Dowlex ™ 2517) on a main surface of the foam. After cooling, the polyethylene layer could be removed from the adhesive. This example illustrates the pressure sensitive adhesive foam with a protective coating. In addition, the compound of two layers can be intertwined with an electron beam to permanently bond the foam to the polyethylene.

Example 38 A sheet of pressure-sensitive adhesive foam was prepared following the procedure for Example 28, except that Hot Melt Composition 8 was fed directly to the twin screw extruder.

Example 39 A sheet of pressure-sensitive adhesive foam was prepared following the procedure for Example 19, except that Composition 9 which Melts by Heat was used and the feed rate of the extruder was 4.5 kg / hr.

Examples 40-42"Foam sheets were prepared by extruding Composition 1 with ethylene vinyl acetate copolymer (EVA)." The EVA for Examples 40, 41 and 42 was Elvax ™ 250 (melt index of 25, acetate content of 28% vinyl), Elvax ™ 260 (melt index of 6.0, vinyl acetate content of 28%) and Elvax ™ 660 (melt index of 2.5, vinyl acetate content of 12%) respectively. HE obtained from DuPont Co. Composition 1 was fed to the extruder at a rate of 2.7 kg / hr and the EVA was fed at a rate of 1.8 kg / hr. A charge of 1.3 pph of expandable polymeric microspheres F100D was used. The extruder temperatures were set at 104 ° C and the temperatures of the hose and nozzle were set at 193 ° C. Additionally, Examples 40 and 41 were co-extruded with a 0.064 mm thick layer of Composition 1 that melts on both major surfaces of the foam. All co-extruded foams were entangled with an acceleration voltage for electron beam of 300 Kev and a dose of 6 mrad. The surface roughness (Ra) of Example 40 was 27 micrometers.

Example 43 A non-stick foam sheet was prepared by following the procedure for Example 40, except that only EVA (Elvax ™ 250) was extruded with 3 pph of expandable polymeric microspheres (F100D). The surface roughness (Ra) was 23 microns on one main surface and 27 microns on the other main surface of the foam.

Example 44 A foam sheet was prepared following the procedure for Example 40, except that instead of EVA a high density polyethylene (Dowlex ™ IP-60 available from Dow Chemical Co.). Feeding rates of Composition 1 and polyethylene were 3.63 kg / hr and 0.91 kg / hr, respectively.

Example 5 A foam sheet was prepared following the procedure for Example 44, except that a low density polyethylene (Dowlex ™ 2517) was used. Feeding rates of Composition 1 and polyethylene were 3.18 kg / hr and 1.36 kg / hr, respectively.

EXAMPLE 46 A foam sheet was prepared by following the procedure for Example 44, except that Composition 9 which Melts by Heat was extruded with a polyester (DinapolTO1157 available from Huís). And 3 pph of expandable polymeric microspheres (F80). The temperature of the extruder was set at 93 ° C and the temperatures of the hose and nozzle were set at 171 ° C. The end plates of the nozzle were set at a temperature of 199 ° C to form a uniform thickness through the sheet. Rates of Feeding of Composition 9 and polyester were 3.18 kg / hr and 1.36 kg / hr, respectively. The resulting foam was cooled and then entangled with an acceleration voltage for electron beam of 275 Kev and a dose of 6 mrads.

Example 47 A non-stick foam sheet was prepared following the procedure for Example 46, except that only polyester (Dynapol ™ 1157) was extruded with 4 pph of expandable polymeric microspheres (F80SD). The foam had a surface roughness (Ra) of 27 micrometers.

EXAMPLE 48 A cylindrical foam of 2.54 cm in diameter was prepared following the procedure of Example 44, except that both Composition 1, Heat Melt and High Density Polyethylene were fed to the extruder at a rate of 2.27 kg / hr with 2 pph. of expandable polymeric microspheres (F80SD). The nozzle was removed so that the foam was extruded into the hose in a cylindrical shape.

Example 49 A cylindrical foam of 1.27 cm in diameter was prepared following the procedure of Example 23, except that both the Heat-Fusing Composition 1 and the block copolymer were fed to the extruder at a rate of 2.27 kg / hr with 2 pph of polymeric microspheres expandable (F80SD). The nozzle was removed and the foam extruded into the hose in a cylindrical shape. 1 Examples 50-52 A foam sheet was prepared for Example 50 by feeding a styrene-isoprene-styrene block copolymer (Kraton ™ Dll07) to the twin-screw extruder of Example 1, at a feed rate of 1.8 kg / hr. An adherent (Escorez ™ 1310 LC, available from Exxon Chemical Co.) was fed into the first port at a feed rate of 1.8 kg / hr, and expandable polymeric microspheres (F80SD) were fed to the third port at a rate of 2 parts. per hundred parts of block copolymer and adherent. The extruder temperatures were set at 121 ° C and the temperatures of the hose and nozzle were set at 193 ° C. The resulting adhesive foam had a density of 539.2 Kg / m3 (33.7 lb / ft3). This sample possessed characteristics of release activated by stretching (i.e., stretch release) as described in US Patent No. 5,507,464 to Bries et al, which is incorporated herein by reference. In Example 51, a foam sheet was prepared following the procedure for Example 51, except that 8 pph of expandable polymeric microspheres F80SD were used. The resulting foam adhesive had a density of 264 kg / m3 (16.5 lb / cubic ft). In Example 52, a foam sheet was prepared following the procedure of Example 51, except that the block copolymer was styrene-ethylene-butylene-styrene block copolymer (Kraton G1657 available from Shell Chemical Co.) and the tackifier was Akron P-90 (available from Arakawa Chemical USA). The resulting foam adhesive had a density of 590.4 kg / m3 (36.9 lb / cubic ft). This sample also possessed release characteristics activated by stretching as described in the US Patent of Bries et al incorporated above and the published PCT Requests.

Example 53 A foam sheet was prepared following the procedure for Example 31, except that the extruder temperatures were set at 93 ° C, and the temperatures for the hose and nozzle were set at 171 ° C. The foam was coextruded into a 0.1 mm adhesive layer on each major surface of the sheet. The adhesive was a sticky styrene-isoprene-styrene block copolymer (HL2646 available from HB Fuller). The resulting foam had a density of 464 kg / m3 (29 lb / cubic foot).

Examples 54-57 The foam sheets were prepared by feeding polyhexene having an intrinsic viscosity of 2.1, to the twin screw extruder at a rate of 4.5 kg / hr and expandable polymeric microspheres (F100D) at a ratio of 2 pph for Example 54 and from 4 pph for Example 55. The foam sheets for Examples 56 and 57 were prepared following the procedure for Examples 54 and 55, "respectively, except that the polyhexene was fed to the extruder at a rate of 3.31 kg / hr. and an adherent (Akron P-115 available from Arakawa Chemical USA) was fed to the first port at a rate of 1.63 kg / hr, and the expandable polymer microspheres were mixed with? .3 pph of 2,4-bis (trichloromethyl) -6-4-methoxyphenyl) -s-triazine before adding to the extruder.

Example 58 Composition 1 that Melts by Heat was processed in a Bonnot screw extruder of 10.16 mm. The extruder was operated at room temperature, counting only on the mechanically generated heat to soften and mix the composition. The mixture was then fed into Zone 1 of a two screw extruder (extruder with two co-rotating Berftorff screws (ZE-40) of 40 mm) where it was mixed with expandable polymer microspheres (F100). A standard combination screw design with forward mixing was used in Zone 2, inverse mixing in Zone 4, Zone 6 and Zone 8, with self-cleaning transport elements in the remaining areas. The screw speed was 125 RPM, resulting in operating pressures of 52.7 kiloPascals and total flow rates of 11.3 kg / hr. The temperatures in the extruder were set at 104 ° C, and the temperatures in the hose and nozzle were set at 193 ° C. This temperature profile prevented expansion during the combination and minimized the rupture of the expandable polymer microspheres. The extruded flow was controlled using a Normag gear pump. The expandable polymeric microspheres were fed to Zone 7 of the twin screw extruder using a Gehricke feeder (GMD-60/2) at a rate of 0.23 kg / h. A jet nozzle measuring 15.24 cm wide, 1 mm thick, was operated at 193 ° C. The sheet was molded on a cold molding roll and laminated to a release protective coating at a rate of 1.5 meters per minute. After coating, the foam sheet was interlaced with electron beam using an ESI Electro Curtain at the dose of 8 mrad, at the acceleration voltage of 300 keV. The resulting foam is shown in Figure 2 (a) and 2 (b). The foam had a surface roughness (Ra) of 37 micrometers.

Examples 59-61 These examples illustrate that they are suitable for use in an on-site foaming application. A foam sheet was prepared for Example 59 following the procedure for Example 3, except that it contained 10 pph of expandable polymeric microspheres F80SD, and the temperatures of the extruder, hose and nozzle were all set at 88 ° C to minimize expansion of the foam in the nozzle. The foam did not interlock and had a density of 880 kg / m3 (55 lb / cubic foot). After subsequent heating at a temperature of 193 ° C for 5 minutes, the density was reduced to 208 kg / cm3 (13 pounds / cubic foot).

Example 60 following the procedure for Example 59, except that Composition 2 which Melts by Heat was used and the temperatures of the extruder, hose and nozzle were all set at 104 ° C. After cooling, the foam had a density of 960 kg / m3 (60 Ib / cubic ft). After subsequent heating at a temperature of 193 ° C for five minutes, the density was reduced to 240 kg / m 3 (15 Ib / cubic foot). A foam sheet was prepared for Example 61 following the procedure for Example 59, except that polyester (Dynapol ™ 1157) was fed to the extruder at a rate of 9 kg / hr, and the temperatures of the extruder, hose and nozzle were they all set at 110 ° C. The 1.14 mm thick foam sheet was entangled with an acceleration voltage for electron beam of 275 Kev and a dose of 6 mrad. "or or Examples 62-70 and Comparative Example Cl Pressure sensitive adhesive foams were prepared following the procedure for Example 3 with varying amounts of expandable polymeric microspheres shown in Table 2. Extruder temperatures were set at 104 ° C, and temperatures The hose and nozzle were set at 193 ° C. Examples 62-66 contained F100D microspheres and Examples 67-70 contained F80SD microspheres. Comparative Example Cl did not contain microspheres. None of the examples were intertwined. The results of the tension (peak stress), elongation and overlap cut test show that the properties of the foam can be controlled by the amount of expandable microspheres, and the addition of the microspheres increased the resistance of the foam to the same compositions as They do not have spheres The overlap cut test used is the same as that described above, except that the sample size was 2.54 cm x 1.27 cm, using a load of 1000 g at 25 ° C.

Example 71 A pressure sensitive adhesive foam was prepared by following the procedure for Example 28, except that 5 pph of expandable polymeric microspheres F100D was used with Composition 2 which melts by heat and a hydrocarbon tackifier (Foral ™ 85 available) was added. at Hercules, Inc. of Wilmington, Delaware). The composition that Funde por Calor was fed to the extruder at a rate of 2.9 kg / hr and the Adherent was fed to the extruder at a rate of 1.7 kg / hr. The extruder temperatures were set at 93 ° C, and the temperatures of the hose and nozzle were set at 177 ° C. The resulting foam was approximately 0.38 mm thick, and subsequently interlaced with a dose of 8 mrad for electron beam at an acceleration voltage of 300 Kev. The adhesive foam was laminated to a flexible retroreflective sheet described in U.S. Pat. No. 5, 450, 235 (Smith et al), incorporated herein in their entirety by reference. The retroreflective sheet with the foamed adhesive was applied at room temperature to a polyethylene barrel (obtained from Traffix Devices, Inc. of San Clemente, California). The barrel was placed in an oven at approximately 49 ° C for 3 days. The barrel was removed from the oven and kept at room temperature for approximately 24 hours. Then the barrel was placed in a truck at approximately -1 ° C for a week. The sheet with the evaluated adhesive showed no delamination or waviness of the barrel at the end of the test period.

Coextrusion by Inclusion Adhesivity The samples of coextrusion by intrusion of the foam were laminated to a 0.127 mm thick piece of anodized aluminum. A strip of tape measuring 1.27 cm by 11.4 cm was cut from the sheet and applied to a stainless steel substrate. The strip was then rolled using four total steps using a 6.8 kg metal roller. The samples were aged for 1 day at 22 ° C, 50% relative humidity. After aging the panel is mounted on an Instron Voltage Tester so that the belt pulls at a 90 degree angle at a speed of 30.5 cm / min (12 inches / minute). The samples were tested both in the machine direction (ie, the direction of the exit flow of the nozzle foam or MD), with the direction of peeling that is parallel to the filaments, as the direction "transverse of the sheet (ie, the direction perpendicular to the direction of flow or CD), with the direction of peeling that is perpendicular to the filaments.The results are determined in pounds by 0.5 inches and converted to Newtons per cm (N / cm).

Stress and Elongation This test was performed according to ASTM D412-92, except as specified. A sample of the foam was cut into a "dog bone" shape that was 2.54 cm wide in the middle portion. The ends of the sample were fixed in an Instron Stress Tester and pulled at a crosshead speed of 30.5 cm / min (12 inches per minute). The test measures the peak stress (in pounds per square inch and is converted to kilopascal (kPa)), and the amount of elongation or peak stretch (in% of the original length) Static Cutting Effort A 2.54 cm by 2.54 cm strip of pressure-sensitive adhesive foam tape was laminated to a 0.51 mm thick stainless steel panel measuring approximately 2.54 cm by 5.08 cm. A second panel of the same size was placed on the tape so that there was an overlap of 2.54 cm, and the ends of the panels extended opposite one another. The sample was then rolled up with a 6.8 kg metal roller, so that the total contact area of the sample for the panel was 2.54 cm by 2.54 cm. The prepared panel was conditioned at room temperature, i.e., approximately 22 ° C for at least 24 hours. The panel was then hung in an oven at 25 ° C and placed 2 degrees from the vertical to avoid a type failure bare. A weight of 1000 grams was hung on the free end of the sample. The time required for the sample with the weight to fall from the panel was recorded in minutes. The static cut samples were tested for failure, and each sample tested exhibited a cohesive failure mode.

Examples 72-84 Foam samples containing submerged thermoplastic filaments were prepared by means of a continuous extrusion which was carried out using a co-extrusion nozzle specially designed as described in a U.S. Patent Application. presented on July 30, 1999, entitled POLYMERIC ARTICLES THAT HAVE SUBMERGED PHASES, which has the following names of inventors: Scott G. Norquist, Dennis L. Krueger, Alan J. Sipinen, Robert H. Menzies, Thomas P. Hanschen, Ronald P. "Leseman, Sharon N. Mitchell, James C. Nygard, Victor P. Thalacker and Jan Ockeloen, which is assigned to the same designation as the present application, and which has an Attorney's file number of 54324USA4A, which is incorporated herein. by reference in its entirety A schematic diagram of these samples is presented in Fig. 4. The continuous foam matrix consisted of Composition 1 which melts by heat with IOTG at the concentration of 0.1% p and 2 pph of expandable microspheres F100D. The adhesive was added to zone 1 of a fully interlaced, two-threaded, 34mm co-rotating Leistritz ™ extruder available from American Leistritz Extruder Corp., Sommerville, New Jersey, adapted with a gear pump. The microspheres were added using a Gehricke feeder (GMD-60) in zone 9 of the two-screw extruder. The temperature profile of the two-screw extruder was: zone 1 = 93 ° C (200 ° F) and zones 2-12 = 104 ° C (220 ° F). The screw configuration of this extruder had two mixing sections before the addition of the microspheres and a mixing section after the addition of the microspheres, while the rest of the screw were transport elements. The two-screw extruder had a screw speed of 100 rpm, a gear pump speed of 7 rpm, and a head pressure of 9.1 MPa (1320 psi) that provided flow rates of 13.6 kg / h (30 lb. / hr). The filament material was a polyethylene-polyokene copolymer (Engage ™ 8200), which was fed to the coextrusion die using a 32 mm (1.25-inch) Killion ™ screw extruder (Model KTS-125 available from Davis- Standard Killion Systems, Cedar Grove, New Jersey) with a length to diameter ratio of 24: 1 and three zones of. barrel operated with a zone temperature profile 1 - 193 ° C (380 ° F), zone 2 - 210 ° C (410 ° F) and zones 3 and 4 - 232 ° C (450 ° F). The screw had a Saxton mixing element with a compression ratio of 3: 1. The 32 mm extruder was run at 10 rpm with a head pressure of 5.1 MPa (740 psi) which provided flow rates of 0.9 Kg / hr (2 lb / h). The filaments were coextruded to immerse in the foam using a 45 cm (18 in) wide Cloeren ™ two-layer multi-dispenser nozzle (available as Model 96-1502 at Cloeren Co., Orange, Texas) that has been modified. The blade had a recessed exit as shown in the previously incorporated case of Attorney File No. 54324USA4A, and the leading edge or tip has been cut to make a blade distributor. The tip of the blade had circular holes, each had a diameter of 508 microns (20 mils) and was separated by a space of 4.1 mm (0.160 in) and extended from the tip of the blade 2.5 mm (0.100 in) in the flow of the matrix. The nozzle was operated at 193 ° C (380 ° F). The foam was molded into a protective paper coating at a speed of 1.2 m / min (4 fpm) resulting in a total thickness of 625 microns (25 mils). The samples were subsequently cured with a beam of electrons using ESI Electrocure from e to an acceleration voltage of 300 keV and dosage of 6 megarads. Example 72 was prepared using the aforementioned conditions with a foam matrix consisting of Composition 1 that Melts by Heat (IOTG = 0.1%) and 2 pph of F100D. No filaments were presented. This was done without operating the KTS-125 satellite extruder. Example 73 was prepared following the procedure for Example 1, except that the concentration of F100D was 4 pph. Example 74 was prepared by means of the aforementioned conditions with a foam matrix of Composition 1 that Fuses by Heat (IOTG = 0.1%) with 2 pph of F100D. The filaments consisted of 10% Dow ™ Engage 8200 polyolefin elastomer p. Example 75 was prepared by means of the aforementioned conditions with a foam matrix of Composition 1 that Melts by Heat (IOTG = 0.1%) with 2 pph of F100D. The filaments consisted of Dow ™ Engage 8200 polyolefin elastomer 20% p. Example 76 was prepared by means of the aforementioned conditions with a foam matrix of Composition 1 that Melts by Heat (IOTG = 0.1%) with 2 pph of F100D. The filaments consisted of Dow ™ Engage 8200 30% polyolefin elastomer p. Example 77 was prepared by means of the aforementioned conditions with a foam matrix of Composition 1 that Melts by Heat (IOTG = 0.1%) with 4 pph of F100D. The filaments consisted of 10% Dow ™ Engage 8200 polyolefin elastomer p. Example 78 was prepared by means of the aforementioned conditions with a foam matrix of Composition 1 that Fuses by Heat (IOTG = 0.1%) with 4 pph of F100D. The filaments consisted of Dow ™ Engage 8200 polyolefin elastomer 20% p. Example 79 was prepared by means of the aforementioned conditions with a foam matrix of Composition 1 that Melts by Heat (IOTG = 0.1%) with 2 pph of F100D. The filaments consisted of 10% Shell Kraton D1107 thermoplastic elastomer p. Example 80 was prepared by means of the aforementioned conditions with a foam matrix of Composition 1 that Fuses by Heat (IOTG = 0.1%) with 2 pph of F100D. The filaments consisted of Shell Kraton D1107 20% thermoplastic elastomer p. Example 81 was prepared by means of the aforementioned conditions with a foam matrix of Composition 1 that Fuses by Heat (IOTG = 0.1%) with 2 pph of F100D. The filaments consisted of Thermoplastic elastomer Shell Kraton D1107 30% p. Example 82 was prepared by means of the aforementioned conditions with a foam matrix of Composition 1 which Funde por Calor (IOTG = 0.1%) with 4 pph of F100D. The filaments consisted of 3445 Exxon Escorene 10% polypropylene p. Example 83 was prepared by means of the aforementioned conditions with a foam matrix of Composition 1 that Melts by Heat (IOTG = 0.1%) with 4 pph of F100D. The filaments consisted of polypropylene 3445 Exxon Escorene at 20% p. Example 84 was prepared by means of the aforementioned conditions with a foam matrix of Composition 1 that Melts by Heat (IOTG = 0.1%) with 4 pph of F100D. The filaments consisted of 3445 Exxon Escorene 30% polypropylene p.

Discussion of Table 3 and Figures 8-10 Table 3 presents a summary of the results of density, adhesiveness, static cut and tension / elongation for Examples 72-84. Only coextrusion samples by inclusion without cross-linking were evaluated for static shear stress. Only cross-linked samples were evaluated for density, adhesiveness and tension / elongation.

Figure 8 shows the separation force as applied in one direction (MD) parallel to the direction of the filament as a displacement function for Examples 73, 77 and 78. This Figure demonstrates that as the filament material increases from 0 to 20% the adhesiveness remains essentially constant. Figure 9 shows the separation force as applied in a perpendicular direction (CD) to the direction of the filament, as a function of the displacement for Examples 73, 77 and 78. Example 73 does not show structure, while Example 77 and 78 dramatically shows different behavior that is characterized by a characteristic frequency and amplitude. The frequency between the maximum in Examples 77 and 78 is exactly the distance between the filaments, note that this period does not change with the concentration. However, the amplitude between the minimum and the maximum does not change dramatically as the filament concentration increases from 10 to 20%. In addition, the adhesion values in the CD direction are higher than in the MD. In this way, by manipulating the concentration of the filament and the distance between the filaments, the peeling behavior can be designed with various qualities both in the parallel direction and in the direction perpendicular to the direction of the filament.

Figure 10 shows the separation force that is applied in a parallel direction (MD) to the direction of the filament as a function of displacement for Examples 72, 79, 80 and 81. This Figure demonstrates that as the filament material increases from 0 to 30% p the adhesiveness is slightly reduced. Figure 11 shows the separation force that is applied in a perpendicular direction (CD) to the direction of the filament as a function of displacement for Examples 72, 79, 80 and 81. Example 72 shows no structure, while Example 79, 80 and 81 dramatically show different behavior that is characterized by a characteristic frequency and amplitude. The frequency between the maximum in Examples 79, 80 and 81 is exactly the distance between the filaments, note that this period does not change with the concentration. However, in contrast to Figure 9 the amplitude between the maximum and the minimum of the force does not change as the filament concentration increases. Therefore, the filament type also plays a role in determining the characteristics of the separation / displacement force ratio. It is not related to the theory, it is believed that as the characteristics of the filament material become more dissimilar to the foam matrix the amplitude between the maximum and the minimum increases. Other unique properties not obtainable by a one-component foam system, but obtainable by co-extrusion by intrusion of submerged discrete structures, could include, for example, longitudinal and inter-filament hand tearing, stretch release, improved tensile properties , designed adhesion (see Figs 9 and 11 and the corresponding discussion). Coextrusion by inclusion of thermoplastic filaments can dramatically increase the tensile strength and elongation characteristics of the materials. These properties can be manipulated by choosing the optimum filament material and filament concentration to produce tension properties ranging from high stress / low elongation to low stress / high elongation. The adhesion behavior in the direction both parallel and perpendicular to the direction of the filament can be manipulated by changing the filament material, filament separation and filament concentration.

Oriented Foam Examples 85-92 One layer (B) foam samples were prepared and of three layers (ABA) as in Example 1, above, except as noted below. Layer A is a layer of non-foamed pressure sensitive adhesive skin formed by using Composition 10 which Melts by Heat. Layer B is a foamed layer formed using the Heat-Fusing Composition 10, various thermoplastic polymer blend components, and various expandable microspheres available from Pierce Stevens, Buffalo, NY. Layer A was approximately 2.5 mils thick, and Layer B was approximately 40 mils thick. The extruder temperatures were set at 93.3 ° C, and the temperatures of the hose and nozzle were set at 176.7 ° C. The thermoplastic blended components were added in various concentrations in zone 1, the Composition 10 that Fused by Heat was added in zone 3, and the expandable microspheres were added in zone 9. The adhesive material pressure sensitive in layers A was fed using a Bonnot 5 cm (2") screw extruder (SSE), either layer A or B was pumped from the extruders to a multilayer feed block using 1.27 cm (0.5 inch) ible tubing. OD. Layers A and B were combined in an ABA array using a Cloeren three layer feed block (Cloeren Company, Orange, TX, Model 96-1501) with an ABA selector shutter. After the two layers were combined in the feed block, the materials were formed into a flat sheet using an Ultra 40 (Extrusion Dies Incorporated, Chippawa Falls, Wl) nozzle of 25.4 cm (10") width. The feed and the nozzle were operated together at temperatures of approximately 176 ° C. The ABA construction exited the nozzle and was molded in a temperature controlled stainless steel molding drum maintained at 7 ° C. After cooling, the foam transferred to a 0.127 mm thick polyethylene protective coating and collected on a film winder The single layer foam constructions were decoupled from Bonnot SSE The foam samples were uniaxially oriented at a ratio in the range of 2.5 : 1 to 8: 1 (ie, stretched in the range of 2.5 to 8 times its length) at room temperature Example 85 was prepared using the aforementioned conditions with a foam matrix consisting of It was composed of Composition 1, which is based on heat at 80% p, 20% p on Dow Engage 8200 and 4 pph on F100D. No layers of adhesive skin (i.e., layers A) were present. The non-interlaced foam samples were oriented uniaxially or stretched 2.5 times their original length (ratio 2. 5: 1) at room temperature. Example 86 was prepared by following the procedure for Example 85, except that the composition of the foam matrix was Composition 1 which Melts by Heat at 40% p, 60% p from Dow Engage 8200 and 4 pph from F100D. Example 87 was prepared using the aforementioned conditions with a foam matrix which consisted of 25% p of Composition 10 which Melts by Heat, 75% p of Shell Kraton D1107 and 4 pph of F80SD. No layers of adhesive skin were present. The non-interlaced foam samples were oriented uniaxially at a ratio of 8: 1 at room temperature. Example 88 was prepared using the aforementioned conditions with a foam matrix consisting of 50% p of Composition 10 that Melts by Heat, 50% p of DuPont Elvax 260 and 4 pph of F80SD. Adhesive skin layers of Composition 10 Melting by Heat (ABA) were presented. The non-interlaced foam samples were oriented uniaxially at a ratio of 2.8: 1 at room temperature. Example 89 was prepared following the procedure for Example 88, except that the composition of the foam matrix was 50% p of Composition 10, which melts by heat, 50% p of DuPont Elvax 260 and 6 pph of F80SD. The samples had minimal elongation and could not be oriented at room temperature. Example 90 was prepared following the procedure for Example 88, except that the composition of the foam matrix was 50% p of Composition 10 that Melts by Heat, 50% p of DuPont Elvax 260 and 9 pph of F80SD. The samples had minimal elongation and could not be oriented at room temperature. Example 91 was prepared using the aforementioned conditions with a foam matrix which consisted of 50% p of Composition 10 which Melts by Heat, 50% p of Shell Kraton D1107 and 4 pph of F80SD. Adhesive skin layers of Composition 10 Melting by Heat (ABA) were presented. The non-interlaced foam samples were oriented uniaxially at a ratio of 6: 1 at room temperature. Example 92 was prepared by following the procedure for Example 91, except that the composition of the foam matrix was 50% p of Composition 10 that Melts by Heat, 50% of Shell Kraton D1107 and 6 pph of F80SD. Adhesive skin layers of Composition 10 Melting by Heat (ABA) were presented. The non-interlaced foam samples were oriented uniaxially at a ratio of 6: 1 at room temperature.

Thermal Crosslinking Examples 93-96 In Example 93, 100 parts of the Heat Melting Composition 19 was mixed with 2 parts of F80 expandable microspheres and 5 parts of the crosslinking agent N, N, N ', N tetracis (2). -hydroxyethyl) adipamide (available as Primid XL-552 in EMS Chemie) and extruded through a nozzle, at a temperature lower than the activation temperature of the Cross link, at a thickness of approximately 1 mm. The resulting foam had a slight amount of gel particles, but did not inhibit the formation and extrusion of the foam. The foam was laminated to a polyester protective coating covered with silicone and cooled. A second silicone-coated polyester release liner was laminated to the adhesive and the laminate was baked in an oven set at 177 ° C for 30 minutes. After cooling, the samples were tested for 90 ° Adhesivity according to the test described above, except that the samples were applied to a metal substrate covered with a DCT5002 automotive paint, and the aging was changed as follows. The results of the test in Newtons / decimeter after aging are: 20 minutes at 22 ° C - 37.8 N / dm 3 days at 22 ° C - 90.0 N / dm 3 days at 100 ° C / 100% humidity - 186.3 N / dm 3 days at 70 ° C - 565 N / dm In Examples 94-96, the adhesives were prepared according to the procedure of Example 93, except that the crosslinking agents and compositions used were as follows: In Example 94, 50.7 grams of Heat Melting Composition 10, 1.1 grams of F80 expandable microspheres, and 5 grams of bisphenol A diclidyl ether (available as Epon ™ 828 from Shell Chemical Co.). In Example 95, 39 grams of Composition 10 that Melts by Heat, 0.8 grams of expandable microspheres F80, 4 drops of a cycloaliphatic epoxy (available as K-54 in Anchor Corp.). In Example 96, 39.2 grams of Composition 10 that Melts by Heat, 0.8 grams of expandable microspheres F80, 0.1 gram of N, N, N ', N tetracis (2-hydroxyethyl) adipamide dissolved in 2 drops of water. Other embodiments are in the following claims. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (39)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A method for preparing an article, characterized in that the method comprises: (a) providing a plurality of expandable polymeric microspheres and a molten polymer composition containing less than 20% p. of solvent, each expandable polymeric microsphere includes a polymer coating and a core material in the form of a gas, liquid or combinations thereof, which expands upon heating, with the expansion of the core material, which, in turn, causes the coating is expanded, at least at the heating temperature; (b) mixing the melt of the molten polymer composition and the plurality of expandable polymer microspheres, under the process conditions, including temperature and shear rate, selected to form an expandable extrudable composition; (c) extruding the extrudable composition expandable through a nozzle to form a polymer foam; and (d) at least partially expanding a plurality of expandable polymeric microspheres before the expandable extrudable composition leaves the nozzle. The method according to claim 1, characterized in that during the expansion step at least partially, the expandable polymeric microspheres are expanded most before the expandable extrudable composition leaves the nozzle. The method according to claim 1, characterized in that during the expansion step at least partially, the plurality of expandable polymeric microspheres are expanded at least partially after the step of mixing the melt and before the composition capable of extruding Expandable leave the nozzle. 4. A method for preparing an article, characterized in that the method comprises: (a) providing a plurality of expandable polymeric microspheres and a molten polymer composition containing less than 20% p. of solvent, each expandable polymeric microsphere includes a polymer coating and a core material in the form of a gas, liquid or combinations thereof, which expands upon heating, with the expansion of the core material, which in turn, causes the coating to expand, at least to the heating temperature; (b) mixing the melt of the molten polymer composition and the plurality of expandable polymer microspheres, under the process conditions, including temperature and shear rate, selected to form an expandable extrudable composition; (c) extruding the expandable extrudable composition through a nozzle to form a polymer foam having a plurality of expandable polymeric microspheres that are at least partially expandable. The method according to claim 4, characterized in that the polymer foam forms at least part of a foaming article on the site. 6. The method according to claim 4, characterized in that the plurality of expandable polymeric microspheres in the polymer foam are at least partially expandable. 7. The method according to claim 4, characterized in that it further comprises heating the article after the expandable extrudable composition leaves the nozzle to cause expansion of the expandable polymeric microspheres. 8. The method according to claim 1 or 4, characterized in that it further comprises interlacing the expandable extrudable composition or the polymer foam outside the nozzle. 9. The method according to claim 1 or 4, characterized in that it further comprises co-extruding the expansible extrudable composition with at least one other polymer composition capable of extruding. 10. The method according to claim 1 or 4, characterized in that it further comprises co-extruding the expandable extrudable composition with at least one other extrudable polymer composition which is an adhesive polymer composition. The method according to claim 1 or 4, characterized in that it further comprises co-extruding the expandable extrudable composition with at least one other polymer composition capable of extruding in the form of a plurality of discrete structures attached to or submerged in the polymer foam. The method according to claim 1 or 4, characterized in that the polymer composition exhibits a cut viscosity, measured at a temperature of 175 ° C and a shear rate of 100 sec "1, of at least about 30 Pascal Seconds 13. The method according to claim 1 or 4, characterized in that the polymer composition contains no more than about 10% by weight of the solvent 14. The method according to claim 1 or 4, characterized in that expandable polymeric microspheres are distributed substantially homogeneously throughout the expandable extrudable composition 15. The method according to claims 4 to 14, characterized in that it further comprises adhering the adhesive article to a desired surface and heating the adhesive article to cause the expansion of the expandable polymeric microspheres, without damaging the adhesive bond between the article and the super 16. The method of compliance with the claim 4, characterized in that it further comprises: (c) permanently positioning the polymer foam on the surface; and (d) at least partially expanding the plurality of expandable polymeric microspheres after the polymer foam is on the surface. 17. The method according to any of claims 1 to 16, characterized in that the article is an adhesive article. 18. The method according to any of claims 1 to 16, characterized in that the polymer foam is an adhesive. The method according to any of claims 1 to 16, characterized in that the expandable extrudable composition is extruded through the nozzle so that at least one surface formed in the nozzle of the polymer foam is smooth ", with a Ra value of less than about 75 micrometers, which is measured by profilometry by laser triangulation 20. An article, characterized in that it comprises: a gap, and a foaming article on the site comprising a polymer foam, which contains a polymer matrix and a plurality of microspheres At least partially expanded expandable polymeric, and optionally an activated gas production agent, the on-site foaming article is positioned in the recess and partially or completely fills the void. 21. The article according to claim 20, characterized in that the on-site foaming article is an adhesive article. 22. The article according to claim 20, characterized in that the gap is defined by at least one of the group consisting of a space between two or more surfaces, two or more opposed and separated substrates, a through hole, and a cavity. 23. An article comprising a polymer foam having major surfaces, with at least one of the major surfaces being open and smooth with a Ra value of less than about 75 micrometers, which is measured by profilometry by laser triangulation, the foam contains a homogeneous distribution of a plurality of thermoplastic expandable polymeric microspheres, each expandable polymeric microsphere is of the type that includes a polymer coating and a central material in the form of a gas, liquid or combination thereof, which expands upon heating, with the expansion of the core material, which, in turn, causes the coating to expand, at least at the heating temperature, characterized in that the plurality of expandable polymeric microspheres is in at least partially expanded condition. 24. An article comprising a polymer foam that includes: (a) a polymer matrix containing a mixture of two or more polymers sufficiently free of urethane crosslinks and urea crosslinks to eliminate the need for isocyanates in the matrix of polymer, and (b) a plurality of partially expanded expandable polymeric microspheres, each expandable polymeric microsphere is of the type that includes a polymer coating and a core material in the form of a gas, liquid or combination thereof, which expands upon heating , with the expansion of the core material, which, in turn, causes the coating to expand, at least at the heating temperature, characterized in that the polymer matrix is made of an expandable extrudable composition having an average molecular weight of at least about 10,000 g / mol. 25. An article comprising a polymer foam that includes: (a) a polymer matrix containing a mixture of two or more polymers sufficiently free of cross-linked urethane and urea crosslinks to eliminate the need for isocyanates in the matrix of polymer, with at least one of the polymers of the mixture containing an adhesive polymer, and (b) a plurality of expandable polymeric microspheres, each expandable polymeric microsphere is of the type that includes a polymer coating and a core material in the form of a gas, liquid or combination thereof, which expands upon heating, with the expansion of the core material, which, in turn, causes the coating to expand, at least at the heating temperature, characterized in that the polymer matrix it is made of an expandable extrudable composition having an average molecular weight of at least about 10,000 g / mol. 26. The article according to claim 24 or 25, characterized in that the matrix of polymer is made of an expandable extrudable composition having an average molecular weight of at least about 50,000 g / mol. 27 Ui article, caracbap 7a ± > because of the polymer foam which includes: (a) a polymer matrix containing two or more polymers, the polymer matrix includes at least one morphology of the group consisting of spherical, ellipsoidal, fibrillar, co-continuous or combinations of the same; and (b) a plurality of partially expanded expandable polymeric microspheres, each expandable polymeric microsphere being of the type including a polymer coating and a core material in the form of a gas, liquid or combination thereof, which expands upon heating, with the expansion of the core material, which in turn, causes the coating to expand, at least at the heating temperature 28. The article according to any of claims 24 to 27, characterized in that at least one of the The polymer contains a pressure-sensitive adhesive polymer and at least one of the polymers is selected from the group consisting of unsaturated thermoplastic elastomers, elastomers saturated insoluble acrylate thermoplastics, insoluble acrylate semi-crystalline polymers, insoluble amorphous acrylate polymers, elastomers containing groups that are activated by ultraviolet radiation, and heat-melt pressure sensitive adhesives prepared from non-photopolymerizable monomers. 29. The article according to claim 28, characterized in that the insoluble amorphous acrylate polymers have a solubility parameter of less than 8 or more than 11. 30. The article according to any of claims 20 to 29, characterized in that the article is one of the group consisting of adhesive articles, seals, articles that seal a space, vibration damping articles, tape backings, retroreflective sheet backings, anti-fatigue grilles, abrasive backs, adhesive pads of markers raised pavement, medical bandages and sealing articles. 31. The article according to any of claims 20 to 30, characterized in that the polymer foam is axially oriented. 32. The article according to any of claims 20 to 30, characterized in that the Polymer foam is an adhesive. 33. The article according to any of claims 20 to 30, characterized in that the foam is interlaced. 34. The article according to any of claims 20 to 30, characterized in that the article comprises at least one other polymer composition in the form of a plurality of discrete structures attached to or immersed in the foam. 35. A multi-layer article, characterized in that it comprises: (a) a first substrate having a main surface and (b) a foam article according to any of claims 20 to 30 on a main surface of the first substrate. 36. The multi-layer article according to claim 35, "further comprising a second substrate having a major surface, characterized in that the foam article is positioned between the first and second substrate. of claims 20 to 30, characterized in that the polymer foam has a surface that follows a pattern. 38. The article according to any of claims 20 to 37, characterized in that the foam has a uniform distribution of the expandable polymeric microspheres. 39. The article according to any of claims 24 to 38, characterized in that the expandable polymeric microspheres are distributed substantially homogeneously throughout the polymer matrix.